1. Field of the Invention
The present invention relates to a radio frequency transformer. More particularly, the present invention relates to a single wire-wound transformer.
2. Description of Related Art
A transformer can transmit energy from one circuit to another circuit via electromagnetic coupling, and main usages thereof are to transform a voltage, change impedance and divide a circuit. During power transmission, the transformer plays an important role. Therefore, the transformer is widely applied to various electronic devices and circuits. In a radio frequency circuit, the transformer is generally used for impedance matching between differential circuits. In the following content, the conventional transformer is described in detail.
In a conventional technique, the transformer is consisted of two separated and corresponding sets of inductor and capacitor, and the two inductors respectively connect different circuits. When uncertain amounts of current pass through a first coil, varied magnetic field is generated. According to an electromagnetic mutual inductance theory, a potential difference is generated on a second coil due to the varied magnetic field. The capacitor is used for generating a resonance with the coil inductor under an operation frequency of, so as to achieve a maximum energy transfer.
It should be noted that the conventional transformer technique applying two inductors for mutual inductance may have rather high energy dissipation for radio frequency band, and the dissipation relates to characteristics of the inductors.